Etchant used in the manufacture of semiconductor devices and etching method using the same

Abstract

A nitride film etchant used in the manufacture semiconductor devices, and an etching method using the etchant, are provided. A wafer having a nitride film formed thereon is introduced into a bathing tube containing an etchant which is a water solution containing phosphoric acid (H 3 PO 4 ) of a concentration of 50-70% by weight and hydrofluoric acid (HF), and the nitride film is etched by the etchant. When the concentration of HF is 0.005 to 0.05% by weight, the etch rate of the nitride film is increased, and the selectivity between the nitride film and an oxide film is kept very high. Also, an etchant containing HF of a concentration of 0.05% by weight is provided as a water solution mixed with H 3 PO 4 and HF. Addition of HF of 0.05% by weight or less increases the etch rate of the nitride film, and a high selectivity of the nitride film with respect to an oxide film is maintained.

What is claimed is:  
     
         1 . An etchant for a nitride film, wherein the etchant is a water solution containing phosphoric acid (H 3 PO 4 ) of a concentration of 50-70% by weight and hydrofluoric acid (HF).  
     
     
         2 . The etchant of  claim 1 , wherein the concentration of HF in the etchant is 0.005-0.05% by weight.  
     
     
         3 . A method of etching a nitride film in the manufacture of semiconductor devices, comprising supplying an etchant bath with an etchant which is a water solution containing phosphoric acid (H 3 PO 4 ) of a concentration of 50-70% by weight and hydrofluoric acid (HF), and introducing a wafer into the etchant bath to etch a nitride film on the wafer.  
     
     
         4 . The method of  claim 3 , further comprising maintaining a temperature of the etchant at 130° C. or less.  
     
     
         5 . The method of  claim 3 , further comprising maintaining a temperature of the etchant at about 120° C. (±5° C.), and the concentration of H 3 PO 4  at about 55-65% by weight.  
     
     
         6 . The method of  claim 3 , further comprising maintaining a temperature of the etchant at about 100° C. (±5° C.); and the concentration of H 3 PO 4  at about 50-60% by weight.  
     
     
         7 . The method of  claim 3 , wherein the concentration of HF in the etchant is 0.005-0.05% by weight.  
     
     
         8 . An etchant for a nitride film, wherein the etchant is a water solution containing hydrofluoric acid (HF) of a concentration of 0.05% by weight or less and phosphoric acid (H 3 PO 4 ).  
     
     
         9 . The etchant of  claim 8 , wherein the concentration of HF in the etchant is 0.005-0.05% by weight.  
     
     
         10 . The etchant of  claim 8 , wherein the concentration of H 3 PO 4  in the etchant is 50-70% by weight.  
     
     
         11 . A method of etching a nitride film used in the manufacture of semiconductor devices, comprising supplying an etchant bath with an etchant which is a water solution containing hydrofluoric acid (HF) of a concentration of 0.05% by weight or less and phosphoric acid (H 3 PO 4 ), and introducing a wafer into the etchant bath to etch a nitride film on the wafer.  
     
     
         12 . The method of  claim 11 , further comprising maintaining a temperature of the etchant at 130° C. or less.  
     
     
         13 . The method of  claim 11 , further comprising maintaining a temperature of the etchant at about 120° C. (±5° C.), and the concentration of H 3 PO 4  at about 55-65% by weight.  
     
     
         14 . The method of  claim 11 , further comprising maintaining a temperature of the etchant at about 100° C. (±5° C.), and the concentration of H 3 PO 4  at about 50-60% by weight.  
     
     
         15 . The method of  claim 11 , wherein the concentration of HF in the etchant is 0.005-0.05% by weight.  
     
     
         16 . The method of  claim 11 , wherein the concentration of H 3 PO 4  in the etchant is 50-70% by weight.